Mould Design Questions

[kc2gvs]

I am entirely a newbie when it comes to Cast Boolits, and have a few questions about moulds and mould designs.

Why are they predominantly wide flat point or round, rather than closer to spire point?

Which seem to work best, rounded grease grooves or squared?

With cast boolit crimp grooves being so much deeper than a simple cannelure, how worried should I be about over working my mouths of my brass?

And finally, I haven't seen any moulds that have the checkering found on some commercial lead boolits. Do they exist, and do the checks really provide any benefit?

Oh, Great and Grand Masters of the Mould, impart upon me, your humble student, your knowledge! Allow me to sup from the font of your wisdom!

[jcren]

The checkering is rolled onto commercial swedged soft lead to hold lube without grooves, square or round grooves is a debate but most claim square holds more lube and has better hydraulic push but round grooves drop from mols much easier. Crimping shouldn't shorten the life of your brass, and in many cases I don't even use the crimp groove. The flat nose lead bullet is the original hollow point, increasing shock and bullet upset dramatically, round nose are preferred for smooth feeding in some actions and spires are used to mimic jacketed for some calipers (7.62) and long range target work. Basically there is no right or wrong answer if it works for your application. Btw, far from an expert myself, and I am sure others will chime in with more specifics.

[kc2gvs]

Thanks a lot, JCren! That has cleared up a ton of questions I've been trying to find the answers to!

[azrednek]

Something to keep in mind with pointy molds. They are a king sized PIA to release from the mold. Use minimal crimp, just enough to keep the castings into place from recoil and your brass' life will be extended. On light recoiling calibers often a slight crimp, just enough to remove the bell is sufficient. On heavy hitters like 44 or 357 mag loaded with slow burning powders like 2400. A heavier crimp is needed not only to hold unfired bullets awaiting in the cylinder in place but the heavy crimp aids with combustion.

You will see better results if you crimp in a separate operation rather than simultaneously with seating. You will develop a just-right feel for just enough crimp that comes with experience.

[gwpercle]

You may already have one , but if not, the Lyman Cast Bullet Handbook has a lot of interesting information, history, why and how concerning nothing but cast bullets. The 4th Edition is in print but if you can get a 3rd Edition it has a lot of good information that didn't get into the 4th. The 4th has some of the new cartridges and load data for other boolit mould makers like Lee and RCBS.
Both are good reads and invaluable if you are into cast boolits.

Welcome from Baton Rouge, La.
Gary

[Wayne Smith]

Spire point boolits tend to suffer from nose slump. That is, the unsupported nose tends to slump asummetricaly when the little light ignites the big light and the boolit gets a huge slap on it's rear end. They tend to be useful under about 1200fps.

[kc2gvs]

Well, OK! More knowledge! And knowing is half the battle, as a cartoon of my youth taught me!

If spirepoints suffer from skewing in the barrel, then I was wondering about Loverin style boolits. Specifically, should I grease every groove?

[Wayne Smith]

Well, OK! More knowledge! And knowing is half the battle, as a cartoon of my youth taught me!

If spirepoints suffer from skewing in the barrel, then I was wondering about Loverin style boolits. Specifically, should I grease every groove?

Not necessarially. Remember that they were designed before we had superior lubes. I typically lube one or two of the grooves with Speed Green or Ben's Red and they work fine. Try yours with a variety of grooves loaded and see how your rifle shoots your lube.

[Good Cheer]

http://i791.photobucket.com/albums/yy192/SNARGLEFLERK/DSCF2862_zps8zl20oyd.jpg (http://s791.photobucket.com/user/SNARGLEFLERK/media/DSCF2862_zps8zl20oyd.jpg.html)

The 45-70 load on the top...
My brother groups sub-MOA with his slap 'em down pure lead swaged shaken baby syndrome 1700FPS hunting loads. And yeah, I wonder about the day when he doesn't remember my name.

[JSnover]

Choose whichever grooves you like, I prefer rounded or angled over square. I believe they shed lube more easily as they travel down the bore and they might drop from the mold more readily.
At cast velocities the nose profile is less important, aerodynamically. Choose one that will feed and be most effective on game.